Software And Hardware Design Of ECU For A Multi-point Injection Methanol/diesel Dual Fuel Engine

As a reliable power mechanism,the internal combustion engine has been invented for more than 100 years,and the internal combustion engines have brought human benefits but also some problems for human survival.The problem of oil resource shortage is getting more and more serious and environmental problems have aroused people's attention.The alternative fuel and dual-fuel technology of renewable fuels are effective measures to solve the above problems simultaneously.Methanol is an ideal renewable fuel and methanol has similar physical and chemical properties to gasoline.In this paper,the electric control unit(ECU)of methanol/diesel dual fuel engine is studied based on the high pressure common rail diesel engine.To conduct the experiment,a set of methanol supply system was added to the common rail engine to form the multi-point sequential injection of methanol/diesel dual engine fuel supply system.The focus of this paper is hardware and software design of ECU for a methanol/diesel dual fuel engine ECU.MC9S12XEP100 MAL was chosen in this paper to control the dual fuel engine.It satisfies the control requirement of experiment of dual fuel engine ECU;Then according to the function of each part of the ECU,such as single chip microcomputer minimum system circuit,the input signal conditioning circuit,power supply circuit,communication circuit,methanol fuel injector drive circuit,MOSFET grid drive circuit,diesel injector drive circuit,fuel metering valve drive circuit and so on,the reasonable circuit design was carried on;Multisim 12.0 was used to simulate the boost converter which is relatively important,the simulation delves into the influence of the capacitor,inductor,power MOSFET of switching frequency and the switch duty ratio on the diesel injector boost converter.Then the boost converter was optimized combining the characteristics of Infineon TLE8386 chip;Finally,the PCB was designed according to the layout,wiring and cooling with the help of Protel DXP 2004.For the software design of ECU,at first,a calibration system was written in C# in this paper.And the stable dual fuel calibration system was designed benefiting from the advantages of object-oriented VS2010 platform in the C# language and efficient characteristics of CAN bus.Based on the functions of the dual fuel ECU and combining the characteristics of MC9S12XEP100 MAL MCU internal resources,A modular design method is used to write the basic program of C language;The control process of injection timing and injection quantity of both diesel and methanol was then detailedly introduced.Then,the control strategy of C.R.pressure based on PI was briefly described.Lastly,the control of injection timing and injection pressure and injection quantity was experimentally verified based on the hardware and software designed and the result shows that the ECU of dual fuel designed in this paper can meet the operating requirement.